There are many well-known bacteria which cause various medical conditions. The bacteria P. acnes has been indicated to be responsible for the acne skin condition in humans, generally known as acne vulgaris, which is the most commonly treated skin condition in the United States. Acne has long been problematic for young adults, but older adults are often affected as well. Effective acne treatment is emphasized, particularly for young people, because of the often long-term consequences, both physical and emotional, which occur due to the unsightly acne skin condition.
Because acne primarily occurs during adolescence, when self-image is being formed, even a mild case can have a profoundly negative effect on the psychosocial development of the individual, including school performance. Further, a moderate to severe acne condition, with its usual long-term scarring effects, can cause disfigurement, often significant, that persists throughout life, which can affect career choice and employment opportunities.
While, as indicated above, acne occurs most frequently in young (adolescent) adults, it is not always resolved by the end of the teenage years and may persist into the 40's for certain individuals. In some cases, the onset of acne may not occur until the mid-20's.
For all the above reasons, it is important to recognize that acne is a significant medical condition, and that it affects a significant part of the population, and many age groups.
Acne treatment includes diet restrictions, antibiotics (both oral and topical), as well as exposure to sunlight and other light sources. Retinoids and hormonal manipulation treatment are also used. Diet restrictions are typically problematic, with unpredictable results. Oral antibiotics have been successfully used to treatment acne, but can have disadvantages, including yeast vaginitis, gastrointestinal side effects and photosensitivity. Retinoids are not advised for women of child-bearing potential and often cause xerosis (dry skin), erythema, cheilitis, conjunctival irritation and alopecia, while hormonal therapy expose the patient to risk of thromboembolism, feminization (in men) and other undesirable effects. Topical antibiotic applications are also used for acne treatment, including retinoids, benzoyl peroxide, salicylic acid and antibiotics. Each of these has their specific undesirable side effects, including undesirable skin surface reactions in some cases.
Light therapy has also been used for acne treatment, including exposure to sunlight. While ultraviolet light has been used in the past in clinical situations to treat acne, such treatment is no longer recommended because of the risk of skin cancer. Existing clinical devices using ultraviolet light are expensive and sufficiently risky that they must be used by medical professionals. The effect of light treatments has in some cases been enhanced by the use of selected photosensitive chemicals. However, such therapy, using a combination of light and selected chemicals, is often uncomfortable, causing stinging, erythema, epidermal exfoliation and hypersensitivity.
New developments in acne treatment involve narrow band light. These developments are illustrated in the following patents and patent applications: U.S. Pat. No. 5,549,660 to Mendes et al uses a light source with a wavelength of 660 nanometers. This, however, has not proven to be particularly effective. Patent Applications No. 20010028227 and 20010023363 to Lys and Harth teach, respectively, the use of light-emitting diodes (LEDs) and 400 watt metal halide lamps which are filtered to emit light in the 407-420 nanometer wavelength range, which has been shown to be effective against certain acne bacteria. The lamps are used to illuminate the entire face. They are large and expensive. LEDs on the other hand are small (on the order of 0.100″) and relatively low cost.
Further, metal halide lamps are inefficient relative to power required and create significant problems in the skin area being treated. A clinical setting and supervision are required. In contrast, LEDs have efficiencies of 15-20%.
There is no effective home use treatment for acne using light. It is hence desirable that an effective treatment of acne using light be developed which is safe, inexpensive and simple to use at home.